Universal transmission tower



Feb. 11, 1930. P. H. THOMAS UNIVERSAL TRANSMISSION TOWER 3 Sheets-SheetOriginal Filed Dec 31, 1926 INVENTOR Feb. 11, 1930. THOMAS 1,746,804

UNIVERSAL TRANSMISS ION TOWER Original Filed D60. 31, 1926 3Sheets-Sheet 2 39 I6 9 a; 71 6a 39 b 31 m 5 7f] 9 20, 24 27 F'IEJOINVENTOR Feb. 11, 1930. THOMAS 1,746,804

Original Filed Dec. 51, 1926 5 She ts-sheet 3 1' November Patented Feb.11, 1 930 STATES mesa-i PATENT GZ 'FEQE Pl-BCY I-I. THOMAS, OF UPPERIvIONTCLAIB, NEW JERSEY UNIVERSAL TRANSMISSEON TOWER The present case isan improvement on my Patent No. 1,616,932, entitled Improvements inuniversal transmission tower, dated February 8th, 1927.

My invention relates to supporting towers for electric transmissionlines and particularly to towers of steel or other material of greatrigidity and strength and offers a particularly rugged and economicalstructure.

I show a tower composed of elements which can be assembled in more thanone relation to accommodate the construction to various conditions atthe point of installation as will appear hereinafter.

This tower makes use of a number or" design principles shown in myPatent No. 1,616,931, entitled Transmission line towers for electriccircuits, dated February 8th, 1927, and my application Serial No.67,159, tiled 5th, 1925, Transmission line towers. V

I have shown in Figs. 1, 2 and 3 a form of tower with tour posts andtransverse guys, located on level ground. Fig. 1 is an elevation takenlooking along the line and toward the l ft in Fig. 3. The lacing in theposts 5*, 5 not shown for clearness. Fig. 2 is an end elevation takenlooking toward the top of the sheet in Fig. 3, certain crossarm membersi not being shown. 8 is a plan view of the left hand end of the tower asshown in Fig. 1.

Figs. 5 and 11 show certain details, espe cially a method for flexiblyconnecting a pair of posts to one end of the crossarm. Fig. 4: is anelevation of an extension 9 of the crossarm taken looking toward the topof the sheet in Fig. 3, and Fig. 5 is a plan of the same. Certainelements are shown partly or wholly by center lines and certain are notshown at all for purposes of clearness. Fig. 11 is a perspective view ofthe construction shown in Figs. 1 and 5, certain crossarm members beingbroken away for the purpose of clearness. This view is taken looking outfrom This application filed. February 6, No. 333 006.

the paper and from the left toward the right in Fig. 2 and from theupper lefthand corner of the sheet toward the end of the crossarm thatis not shown in Fig. 3. In Figs. 1, 5 and 11 certain members at the endof the crossarm supporting the conductor 2 are not shown.

In Fig. 6 the same tower is shown located on ground sloping across theline making an inclination of 525% with the horizontal, this view beingan elevation taken the same as 1. Fig. 7 is an elevation of the sametower taken looking across the line located on ground sloping both alongand across the line. Figs. 8 and 9 are respectively an end view and apartial plan respectively of air ther form of tower made up of the sameelements as the tower of Fig. 1 and having two posts only, but havingboth transverse and longitudinal guys. Certain parts are omitted forclearness.

Fig. 10 shows an elongated post for applicants tower, having anextension inserted at .ne middle.

in Figs. 1, 2, 3, t and 5, showing a tour post form of tower, 1 is acrossarm supporting six electrical conductors, 2, 2, and two groundwires 3, 3. Insulator strings supporting the conductors are shown at l,l. The crossarm 1 is trained preferably of steel members such structuralangles put together in the usual way. The crossarm may be supported bytwo pairs of posts 5, 5 and 5 5" attached to the crossarm 1 at theirupper ends, but spread apart lengthwise of the line at the lower ends.The posts may be supported on any suitable foundations 6, 6 at theground level, tripods being shown in the illustrations. lhese posts areso designed and connected to the cross that no material bending momentwill be introduced in the posts by any movements of the crossarm withinreasonable limits. The crossarm will normally be held firmly in )laceagainst all stresses acting on it, but should a foundation settle, or aconnection stretch a little or the guys be tightened unevenly, therewould be a certain movement of the crossarm but this would throw nobending stresses into the posts. This is important since bendingstresses would be very severe on the posts.

Similarly the posts are so connected. to the foundations or thefoundations are so designed that any angular movement of the postscorresponding to the limited movement 1 of the crossarm alreadydescribed will not throw bending stresses into the post. The post may behinged to the foundations as shown for longitudinal motion in Figs. 1and 2 where the post is carried on a bolt 35, which in turn passesthrough the tops of the three angles 36 connected in the form of atripod, with a base 37, or the connection may merely be designed forflexibility as for example, as shown for transverse motion in Figs. 1and 2 also.

The crossarm is restrained from lateral motion by the transverse guys 7and 8. Each of these guys is connected to an extension 9 fastened to thecrossarm 1 and divides at the connector or equalizer 7 and 8 into twoguy rods, 7 7 b and 8 8 respectively. These divided guy rods areconnected to anchors or foundations near the bottom of the posts 5 and 5as shown. By this arrangement I secure the distribution of the stressesproduced in the posts by the transverse pull on the crossarm and whentheguys are connected directly to the foundations of the posts, as hereshown,

" the weight of the tower and its load at each post is in opposition toany uplift on the guy. I further secure an attachment of the transverseguys 7 and 8 to the crossarm 1 in such a way that no bending in a planeperpendicular to the crossarm is produced and no bending stresses in theposts. This arrangement further serves to give an indication of therelative tightness of either pair of guys 7, 7 or 8*, 8 for theconnectors 7 and 8 will be pulled to one side if either guy of the pairis too tight. The guys 7 and 8 are attached to the extensions at a pointon the central plane of the crossarm.

Longitudinal stresses on the crossarm whether due to conductors, groundwires, wind or other cause are taken up by horizontal components of theaxial stresses in the posts, for these posts taking no bending have onlyaxial stresses. The vertical components of the stresses in the posts dueto horizontal longitudinal stresses on the crossarm are equal and ofopposite sign and neutralize each other at the top. 7

All downward stresses including the weight of the crossarm are dividedbetween the four posts according to the well known laws of mechanics. V

I have not shown the details of the particu lar framing of the crossarmor the posts and foundations for this will be evident to those areattached the posts 5 5 5, 5 and de tails of suitable connections betweenthe posts and the crossarm. In these figures I have used center lines orgauge lines largely to represent the steel members which will usually beof structural steel angles. I have shown portions of angles in outlinewhere this is necessary for clearness. Fig. 11 shows in perspective thesame construction as Figs. 4 and 5, the same numerals being applied tothe same members in all the figures. The crossarm is shown as extendingbackwardly and to V the right. The angles 33, the plates 30, 30, 22',23, 24; and bolts 25, 26 and 27, forming the flexible connectionsbetween the posts and the crossarm are shown clearly. The members 19, 20are braces boltedto the flanges of the angles 12, 13 and 17, 18.

Referring to Fig. 1, 10 is a strut or tie angle, being a part of thecrossarm shown also in Fig. 3 and in Fig. 7. This is the member to whicha ground wire may be connected when used. This member 10 connects thetwo main crossarm chord angles 28, 28.

The post 5 is connected to the extension 9 by two heavy bolts 25 and 26acting as hinges between the crossarm and the post for motion of thecrossarm transversely. In the post these bolts are carried by two pairsof plates 30, 30, bolted or riveted to the main angles 31, 31, of thepost- 5 two angles being connected to one pair of plates. These bolts 25and 26 pass through holes in the plates 22 and 23 which are part of thecrossarm extension 9. this securing the posts to the crossarm in such amanner as to permit free motion of the crossarm transversely withoutputting bendmoment in the posts. This connection, however, is stifiagainst angular motion in the plane containing the axis of the post andthe two bolts 25 and 26. This stiffness is useful in steadying thecrossarm against wind pressure along the line, which would otherwiseoverturn the crossarm. However, this wind pressure is only that actingon the mem bers abovethe plane of the angles 28, for stressin that planeis resisted by the posts by axial stresses, these posts having theiraxis meeting in the line of the centers of the members 10, see Fig. 4.The residual bending moment of longitudinal wind must be taken by theposts but will be so small as to be unobiectionable. The postis given asuitable cross sectional shape for this purpose.

The plates 22 and 23 taking the stresses from the post are carried bytwo angles 12 and 13 connecting to the plate 21 secured to the member atits center and the angles 16 and 17 connected at the point 29 (see Fig.5) to the angles 39, 39, which are extensions of the angles 28, 28 andalso to the angle 32' (see Fig. 1) from above. The plates 22 and 23 areconnected together by the angle 19, secured to the legs of the angles 12and 13.

The post 5 is connected to the crossarin extension 9 through the plate2% by means of the bolt 2?, much in the same way as post 5., but asingle bolt is used so that the connection may be flexible bothtransversely and longitudinally. The plate 2 1 and the bolt 27 aresecured to the post at the center point of its top by two angles 33,which run across the post to transfer the stresses to the plates 30, 30and the main corner angles 31. The plate 24 is carried by the angles 14and 18 connected respectively to the plate 21 and to the angles 16 and17 and 32 at the point 29. The plates 23 and 24 are connected togetherthrough the angle 20. It will be noticed that a transverse movement ofthe crossarm 1 will tend to bend the plates 22, 23 and 2%, since they donot lie strictly in parallel planes. However, in practice this will beof no disadvantage because for any degree of motion likely to exist theamount of this bending will not be important and because the posts arefree to rotate on their axes to a certain extent.

The angles 11 and connect the plates 22 and 2% to the angles 28 at theirpoint of connection to the ends of the member 10, securing the cross-armagainst overturning.

There is advantage in using a connector or equalizer 3% at the pointwhere the guys 7 8 and 7 8", cross as this supports these guys and givesa certain control of the clearance between the conductors 2 and the guysby determining the angle at which the guy 7 or 8 leaves the post top.

Turnbuckles or other length adjustment means 10 should be inserted inthe guys at a sufficient number of points to permit adj i...t ment ofstress and position for all guys.

Certain members have been omitted in these figures to clarify thedrawings so that the construction may be clear, but they may easily besupplied by those skilled in the art.

This tower of Figs. 1, 2 and 3 may be used on sloping ground. If theslope is across the line, the posts may still be placed vertical and theguys readjusted as shown in Fig. 6. In this case the crossarm will begenerally parallel to the surface of the ground. The clearance from theconductors to the guys will be somewhat affected but not seriously andin any case any desired clearance may be provided for by design. Thisuse of my tower avoids the necessity of excavation of the ground on thehigh side or building up under the posts on the lower side on suchsloping ground. This is often of very great advantage.

hen the ground slopes with the line the tower may be installed on the.actual surface of the ground as it lies throwingthe center line of thetower of]? the vertical and for reasonable slopes no materialdisadvantage re: sults. The stresses due to dead load are increased onthe downhill posts but the stresses due to longitudinal load aredecreased on this post, so that for reasonable angles no specialconstruction is required. This condition is shown in Figure 7, in whichthe tower of Fig. 2 is shown on ground sloping both with and across theline, the ground under the back posts being the higher. In Figs. 6 and Tthe same posts are designated; by the same numerals as in Figs. 1, 2 and3. In Fig. 7 some members have been omitted for the sake of clearness,but they may be readily supplied by those skilled in the art.

By this method of adjusting the tower to the slope of the ground I avoidmuch expense and diiiiculty in side hill extensions such as are requiredin many towers of the standard type.

In general I prefer to fabricate the posts in two parts, such partingbeing assembled and galvanized in the shop and the two being boltedtogether in the field, the separation be ing at or near the middle ofthe section being square at this point. In this case all four posts maybe made of identically the same members, the top halves being assembledon the lower halves with the post 5 in a position at right angles tothat for posts 5*. The plates 30, 30 may be used in all post tops butthe angles 33 must be added in post 5 to carry the bolt 27. i

There circumstances permit I may use two posts, for example, two posts 5of Figs. 1, 2 and 3 in place of 4. In this case I add longitudinal guys38, Fig. 8, connected to each post preferably at the middle point of themember 10 of the crossar-m corresponding. to. the member 10 of the Figs.1, 2 and 3, these guys taking up longitudinal stresses. In this case thecrossarm extension S) corresponding tothe extension 9- of Figs. 1, 2, 3.must be somewhat differently framed since there is but one post to beconnected. Such framing need not here be shown as it involves no novelproblems. The extension 9. is symmetrical about a vertical plane throughthe middle. of the crossarm.

This tower of Fig. 8 is shown in plan in Fig. 9, where similar parts aresimilarly numbered. One of the transverse guys for the structure ofFigs. 8 and 9 is shown at 7, the other guy 8 being. similar butoppositely placed. The longitudinal guys 3.8 may to advantage make asmall angle with the, center line of the transmission line to give alittle support to the transverse guys and to improve the clearance fromthey conductors.

other members of the tower.

-As shown in the various figures, on account of the transverseflexibility of the connections between post 5 and the crossarm, andwhere four posts are used the flexibility in both directions of theconnection between the post 5 and the crossarm, the structure as a wholemay be subjected to sinking of foundations, irregularities ofinstallition, stretching or improper adjustment, of guys, etc., withoutthrowing undue stresses into the posts or V This is in contrast to theconditions in the standard four legged type of tower, wherein anyyielding of foundations must cause serious strains in the rigidstructure.

The present type of tower gives what might be called a universalstructure which may be used for many sorts of sites and conditions asmay be most convenient. Where ground space is important the arrangementof Figs. 1, 2 and 3 is suitable, while that of Figs. 8 and 9 is usuallymore economical:

where guys may be permitted. The arrange ment of Flgs. 8 and 9 issimilar 1n many re spects to structures shown in my applicationsreferred to. 7

It will be noted that certain elements, the more important parts, arethe same in all uses Serial No. 67,159 and Patent 1,616,931 above ofthetower, while certain other parts, large:

ly the connections, vary for different ground conditions and othercauses. For example, both the upper and lower post sections are all the,same, also the crossarm is always the same, excepting the extension 9 or9 which in thissense is to be taken as attached to the crossarmratherthana part of it.

The material and form of the guy also re nains the same although thelength varies. The connections, as for example the bolt hinges, aredifferently arranged for difierent embodiments also the guy connectionsand the guy lengths. This layout is favorable for economy for thespecial parts for the line as a whole are reduced to a minimum. Wherethe slopes of the ground are not uniform or where desirable for otherreasons, I contemplate the lengthening of one or more posts to conformto the ground or other condi tions. This lengthening is accomplishedpreferably by inserting a length of post between the top and bottomelements above described. Such an extension piece is shown in Fig. 10,where the member 41 is inserted between the post top 42 and the postbottom 43 of the post 5*.

I claim as my invention:

1. A transmission line tower comprising a transverse crossarm carryingattachment points for conductor supports thereon, located in a plane ofattachment, a foot on each side of the center under said crossarm andrigidly framed thereto, a single post under each of said feet takingdownward axial loads and hinged to said foot to permit motion across theline while resisting overturning. of

said crossarm, means for restraining motion across the line consistingof'crossed ties connected to the points of connection between said feetand said posts and means for re-' tion across the line consisting ofcrossed ties attached at one end to the connection between the posts andthe feet and at the other near the base of the opposite post and meansfor restraining longitudinal motion of said crossarm, said means beingattached to said crossarm in said attachment plane.

3. A transmission line tower comprising a transverse crossarm carryingattachment points for conductor supports thereon, located in a plane ofattachment, a foot on each side of the center under said crossarm andrigidly framed thereto, a single post under each of said feet takingdownward axial loads and hinged to said foot to permit motion across theline while resisting overturning of said crossarm, means for restrainingmotion across the line consisting of crossed ties connected to thepoints of connection between said feet and said posts and means forrestraining longitudinal motion of said crossarm, said means beingattached to said crossarm. 7

4. A transmission line tower comprising a transverse crossarm carryingattachment points for conductor supports thereon, located in a plane ofattachment, a foot on each side of the center under said crossarm andrigidly framed thereto, a single post under each of said feet takingdownward axial loads and hinged to said foot to permit motion across theline while resisting overturning of said crossarm, means for restrainingmotion across the line consisting of crossed ties connected to thepoints of connection between said feet and said posts and means forrestraining longitudinal motion of said crossarm, said means consistingof guys in pairs connected to said crossarm in the plane of said cablesupports.

5. A conductor carrying crossarm having a horizontal truss for resistinglongitudinal stresses, feet under said crossarm framed rigidly theretoon opposite sides of the center, a single post bearing axial stressesunder each of said feet, hinged joints between said posts and said feetpermitting freedom of motion only across the line, foundations undersaid posts, and m ans for restraining motion across the line consistingof crossed tension members secured at the top to the connecting pointsbetween said posts and said feet and at the bottom to said foundations.

6. A transmission line tower comprising a transverse overhangingcrossarm, a single post supporting said crossarm on each side of thecenter and foundations under said posts, said posts being each providedat the top with two separated hinge joint bearings operating in oneplane and at the bottom with a single hinge joint bearing operating in aplane at right angles to said first named plane.

7. A post in an articulated transmission line structure comprising along column designed to take axial stresses, two hinged bearings at thetop spaced apart in a direction along the line and a single hingedbearing at the bottom set at right angles to said first named bearings.

8. A post in an articulated transmission line structure comprising alongcolumn designed to take axial stresses, two hinged bear ings at the topspaced apart in a direction along the line and a single hinged bearingat the bottom set at right angles to said first named bearings, saidpost consisting of three members, an upper member and a lower memberboth having tapered main legs and a central member having parallel mainlegs connected to said members with tapered legs.

9. A transmission line tower comprising a transverse crossarm, carryingattachment points for conductor supports thereon located in a plane ofattachment, two compressi-on members under said crossarm one on eachside of the center, hinges on said crossarm to permit motion of thecrossarm across the line, while resisting overturning of said crossarm,said hinges being located below said plane of attachment and means forrestraining displacement of said crossarm longitudinally andtransversely, the forces resisting transverse displacement being appliednear said hinges.

10. A transmission line tower comprising a transverse crossarm, carryingattachment points for conductor supports thereon located in a plane ofattachment, two compression members under said crossarm one on each sideof the center, hinges on said crossarm to permit motion of the crossarmacross the line, while resisting overturning of said crossarm, saidhinges being located below said plane of attachment and means forrestraining displacement of said crossarm longitudinally, said meansbeing attached to said crossarm in said plane of attachment, togetherwith crossed ties restraining transverse displacement of said crossarmconnected near the opposite ends of said compression members.

11. A transmission line tower comprising a transverse overhangingcrossarm, a single

